The present application is directed to devices and methods for treating a spinal deformity and, more particularly, to tethering devices and methods that apply a corrective force to one or more vertebral members.
The spine is divided into four regions comprising the cervical, thoracic, lumbar, and sacrococcygeal regions. Vertebral members of the spine are aligned in a curved configuration that includes a cervical curve, thoracic curve, and lumbosacral curve. Various deformities may affect the normal alignment and curvature of the vertebral members. Scoliosis is one example of a deformity of the spine in the coronal plane, in the form of an abnormal curvature. While a normal spine presents essentially a straight line in the coronal plane, a scoliotic spine can present various lateral curvatures in the coronal plane. The types of scoliotic deformities include thoracic, thoracolumbar, lumbar or can constitute a double curve in both the thoracic and lumbar regions. Schuermann's kyphosis is another example of a spinal deformity that affects the normal alignment of the vertebral members. One or more tethers may be attached to the vertebral members to reduce and/or eliminate the deformity.
Tethering is often used with patients with growth potential of the bony members including prepubescent children less than ten years old who have yet to experience a growth spurt, and adolescents from 10-12 years old with continued growth potential. The tethering system should accommodate the expected continued growth of the patient after the implantation. Damage to the patient and/or the tethering system could occur if the system is not able to accommodate this growth.